Two-stroke cycle combustion engine



A. O. L. WENNERBY TWO-STROKE CYCLE COMBUSTION ENGINE Filed 001;. 18, 1923 2 Sheets-Sheet 1 Jig-1 JEN/03;

TWO-STROKE CYCLE COMBUSTION ENGINE Filed Oct. 1 1923 2 Sheets-Sheet 2 Patented cc. 2, 1924.

: m u x k a A. Z 2 i ARTHUR OSKAR LEONARD WENNEEBY, O'F HALMSTAD, SWEDEN.

TWO-STROKE CYCLE COMBUSTION ENGINE.

Application filed October 18, 1923.

I '0 all whom c't may concern.

Be it known that I, ARTHUR OSKAR LEONARD T ENNERBY, a citizen of the Kingdom of Sweden, and residing at Halmstad, in the county of Halland, Kingdom of Sweden, have invented a new and useful Improvement in Two-Stroke Cycle Combustion Engines, of which the following is a specification.

This invention relates to an improvement in two-stroke cycle combustion engines of the kind provided with a preferably doubleacting compressor for compression of the air needed for the combustion and for scavenging of the working cylinders. Although the invention is mainly intended for use in combustion engines adapted to be driven by means of heavy oils it is not limited to such use but may be used also in engines driven by benzene and the like. The object of the invention is to obtain a greater running speed of the engine in order by means of a smaller engine to obtain a greater number of horse-powers than hitherto has been possible. 7 In two-stroke cycle engines the speed of the engine, i. e. its number of revolutions per unit of time, is limited upwards on account of the fact that the exhaust gases must be given a sufficient time to be expelled from the working cylinders and to be substituted by fresh air for each working stroke of the engine piston, and since in two-stroke cycle engines every other stroke of the pistons is a working stroke it will easily be understood that the maximal number of revolutions per unit of time is high-- 1y dependent upon the rapidity of the exchange of gases within the cylinders. Already by using a preferably double-acting compressor for compression of the air used for scavenging and combustion purposes within a separate chamber, within which the air is always maintained under pressure, the maximum number of revolutions per unit of time of the engine may be substant-ially increased, but the number of revolutions may be still further increased if the compressed air is admitted simultaneously into both ends of the cylinders, as proposed according to the present invention.

In the accompanying drawings the invention is illustrated with reference to a two-cylinder engine, but by those skilled in the art it will be obvious from the fol- Serial No. 669,372.

lowing description that the invention may be used as well in combination with singlecylinder engines as with engines having more than two cylinders.

In the drawings Fig. 1 shows a cylinder casting seen in longitudinal section along the line (4-?) in Fig. 2, which latter shows a cross section along the line ccZ in Fig. 1. Fig. 3 shows a section along the line 6-7" in Fig. 1 and Fig. a a section along the line g-h in the same figure.

In the drawings the cylinder casting shown belongs to a vertical engine, but of course the invention. may as wellbe used in combination with engines having horizontal cylinders, which will be understood without further.

In the modification shown in the draw ings the two working cylinders are referred to by the numerals 1 and 2, and a compression cylinder 3 is preferably placed between two adjacent working cylinders, as shown in the drawings, although the latter cylinder may also be placed in a different way. The compressor is supposed to be doubleacting and the inlet port or ports for the fresh air are located at the centre part of the cylinder 3. The discharge from the compressor takes place through valves (not shown in the drawings) arranged at bot-h ends of the compression cylinder 3, whereafter the compressed air is accumulated within compression chambers 5 and 10, Figs. 1 and, 2 preferably but not neces sarily located within a hollow cover common to all of the cylinders, therebymaintaming a certain pressure within said chamber.

This compression arrangement is known in itself and is independent of the present invention forming no part thereof, and said arrangement may be varied according to circumstances, since with regard to the invention the main condition is only that a supply of compressed air is always at hand irrespective of the manner, in which it is performed and irrespective of the means whereby the same is transmitted to the engine cylinders. By using the invention in combination with engines provided with a compression arrangement of the construction described the performing of the invention in practice is, however, extremely simplified, since all of the air channels needed may be located within the cylinder casting, as described below.

At the end opposite to the crank shaft the working cylinders in a manner previously known are provided with air inlet port or ports, such ports being controlled by means of valve 6 (Fig. l) and after completing the working stroke the exhaust gases are expelled through outlet ports 7 which ports are uncovered by the piston near the end of its working stroke.

According to the invention each working cylinder is provided with one or more air inlet ports 8, which are in constant com mnnication with the compression chamber 5, whether it is locatec within the hollow cylinder cover or not, and such communication, in the modification shown, being effected by means of channels 9 placed along the exterior of the compression cylinder (compare Fig. 2). The air inlet ports 8 are preferably but not necessarily placed diametrically opposite to the exhaust ports 7, and suitably the first mentioned ports are given such dimensions and shape that the exhaust ports 7 are uncovered by the pistons a little moment previous to the uncovering of the air inlet ports 8. Suitably the shape of the ports in question is so chosen that the ports 7 are about half open when the opening of the ports 8 commences and that full opening is reached simultaneously for both kinds of ports (compare Fig.

In case of air cooled engines it is possible to arrange the ends of the compressed air channels adjacent to the crank shaft end of the cylinder in almost any way, but in case of water cooled engines they may suitably be arranged in the manner shown in the drawings, i. e. so that between the water jacket and the cylinders and in a cross section plane in level with the ports 8 there is placed a transversal channel 10 (Figs. 2i-) connected by means of the channels 9 with the compression chamber 5. If the compression chamber is not located within the cylinder cover the connection between the same and the channel 10 may of course be carried out in any other way as found convenient with regard to the location of said chamber.

At the end of the working stroke the exhaust at first takes places through the ports 7 as usual, as long as only said ports are open. Thereafter the ports 8 are, however, also uncovered and the compressed air blown into the cylinders through the latter has an ejecting effect and it very rapidly expels the last portion of exhaust gases from the cylinders. The valves 6 are opened substantially at the same time and fresh combustion air very rapidly fills the cylinders from the other end. Therefore the exchange of exhaust gases for fresh air is highly facilitated by the invention and consequently the number of revolutions per unit of time may be substantially increased Without impairing the efiiciency of the engine.

What I claim as my invention, and desire to secure by Letters Patent is 1. A two-stroke cycle combustion engine, including a number of working cylinders, a compression chamber common to all the cylinders, a compressor for accumulating air under pressure in said chamber, and means for establishing communication between said chamber and each cylinder at the respective upper and intermediate the ends of said cylinder relative to the stroke of the piston, and. an exhaust port for the cylinder arranged adjacent the lower end of the cylinder.

2. A two-stroke cycle combustion engine, including a number of working cylinders, a compression chamber common to all the cylinders, a compressor for accumulating air under pressure in said chamber, and means for establishing communication between said chamber and each cylinder at the respective upper and intermediate the ends of said cylinder relative to the stroke of the piston, and an exhaust port for the cylinder arranged adjacent the lower end of the cylinder, the exhaust port communicating with the cylinder in advance of the opening of the adjacent compressed air inlet.

3. A two-stroke cycle combustion engine, comprising a plurality of working cylinders, a piston in each cylinder, a cover common to all the cylinders, said cover being formed with a compression chamber common to all the cylinders, an air inlet from said compression chamber to each cylinder arranged adjacent the upper end of the cylinder, an air inlet from the compression chamber to each cylinder arranged adjacent the lower end of the cylinder as detii'ied by the limitof movement of the piston, an exhaust port leading from the cylinder arranged adjacent the lower end thereof as defined by the piston movement, the lower margins of the lower air inlet and exhaust port being on a plane with the upper margin of the exhaust port above that of the adjacent air inlet.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses.

ARTHUR OSKAR LEONARD WENNEREY.

lVitnesses T. LUNDBERG, M. CARLSSON.

lltl 

